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利用智能温湿度传感器、8位单片机、键盘数字显示模块控制器构成一种高集成温湿度测量系统,该测量系统具有传感器非线性补偿、温度补偿、自校准以及断电保护现场置入等功能,可用于温度、湿度和露点的精确测量。 相似文献
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浓度校准是气体分析仪器实现准确定量检测的前提,浓度校准需采用气体稀释系统。本研究将比例积分(Proportional integral, PI)算法与双流法结合,发展了一种新的湿度控制方法,即PI-双流法,并基于此建立了一套具有湿度调控功能的气体稀释新系统。首先,对系统中重要部件加湿器的性能进行考察,结果表明,加湿器出口处的相对湿度(Relative humidity, RH)存在一定波动(96%~103%),因此,本系统通过引入自整定PI控制算法来减小波动对整个系统湿度控制精度的影响。随后,对新系统的性能进行考察,结果表明,本系统的RH调控范围为5%~100%, RH准确度最高可达0.026%RH(25℃,100%RH),调节时间最快可达38 s (25℃,500 mL/min),可跟踪周期大于175 s的正弦输入。在不同温度和RH条件下,研究了湿度对PTR-MS反应离子分布的影响,结果表明,本系统可在较宽湿度范围(10%~100%)内满足进样流量大且连续进样气体分析仪器(如PTR-MS)的应用需求。本系统有望用于受湿度影响的气体测量仪器的校准。 相似文献
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《理化检验(化学分册)》2016,(4)
正按照国际标准对标准样品的新定义:一种或多种规定特性足够均匀或稳定的材料,已被确定其符合测量用途的~([1])。冶金块状标准样品根据预期用途可分为系列标准样品、类标准样品、再校准样品和检查样品~([2])。系列标准样品和类标准样品用于材料赋值与质量控制,再校准样品用于测量系统校准,检查样品用于测量系统评估。其中,系列标准样品和用于给材料赋值的类标准样品为有证标准样品,亦即其特性量值具有溯源性;而再校准样品的预期用途 相似文献
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自行开发了适用于标准《石油产品常压蒸馏特性测定法》的结果计算程序,可自动实现校准数据引入、测试结果数据计算、测试结果超差判断、报表打印页生成等工作. 相似文献
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介绍有害气体检测传感器研究进展。气体检测传感器主要有催化燃烧式传感器、热导式传感器、电化学传感器、红外传感器、金属氧化物半导体传感器、碳纳米管传感器等,基于气体传感器的检测原理,综述了常用气体检测器的应用范围和局限性。催化燃烧式传感器可以灵敏地检测爆炸下限以下可燃气体的浓度,但需注意防止其暴露于高浓度气体环境中;热导式传感器无需氧气供应,适用于检测热导率比空气高的低相对分子质量气体;电化学传感器对检测环境的温度、湿度变化敏感,适用于检测具有电化学活性的气体;红外传感器无需定期校准,适用于检测腐蚀性和反应性气体,但无法检测单质气体;金属氧化物半导体传感器可在高温环境下工作,并能灵敏地检测浓度为10–9 mol/mol的气体;碳纳米管传感器只能用于检测强氧化还原性气体,通过对碳纳米管材料进行修饰改造可扩展其应用范围。最后对气体检测传感器的发展进行了展望。 相似文献
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《Spectrochimica Acta Part B: Atomic Spectroscopy》1999,54(13):1821-1829
Analyte transport efficiencies of solid as well as liquid samples were determined for electrothermal vaporization (ETV). A graphite furnace of the boat-in-tube type was employed for ETV. The generated aerosol was transported by an argon flow via a tubing into an external precipitator and deposited on a L’vov platform with a corona-like discharge. The sample on the secondary platform was analysed with a laboratory-constructed coherent forward scattering multielement spectrometer. For determining the analyte transport efficiencies, the comparative measurements were carried out with standard solutions dosed directly on the platform in the spectrometer furnace. The simultaneously investigated elements were Cu, Fe and Mn in the standard reference material BCR CRM 189 wholemeal flour and in a multielement standard solution containing approximately the same element ratio as certified for the solid sample. ETV boat-to-L’vov platform transport efficiencies of approximately 19% for Cu, 24% for Fe and 19% for Mn were calculated for both solid samples and multielement standard solutions. Cu, Fe and Mn in wholemeal flour were determined simultaneously by calibrating against aqueous multielement standard solutions injected into the boat as well as by the standard addition method. The results agree satisfactorily, the deviations from the certified values are below 10% and the relative standard deviations are typically 5–8%. The limits of detection are 250 pg for Cu (λ=324.8 nm), 230 pg for Fe (λ=248.3 nm) and 90 pg for Mn (λ=279.8 nm), loaded into the ETV boat. 相似文献
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《Journal of mass spectrometry : JMS》2017,52(1):30-35
We examine the potential for PTR‐TOF‐MS systems to quantitatively measure glyoxal in ambient air by characterizing the response of the instrument to a dilute glyoxal sample, calibrating the system as a function of humidity. The concentration of glyoxal in a sample air‐stream was measured with an UV absorption spectrometer in parallel to a PTR‐TOF‐MS. This calibration demonstrated that the PTR‐TOF‐MS has a relatively low sensitivity to glyoxal particularly at high humidity. Extensive fragmentation of glyoxal to formaldehyde was observed. This behaviour not only desensitizes PTR‐MS system to glyoxal; it may also pose a problem to the quantification of formaldehyde. © 2016 The Authors. Journal of Mass Spectrometry Published by John Wiley & Sons Ltd. 相似文献
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László Kiss Zsuzsanna Őri Lívia Nagy Barna Kovács Géza Nagy 《Journal of Solid State Electrochemistry》2013,17(12):3039-3045
In voltammetric analysis the signal—in most cases—depends on transport processes. When getting concentration values of analytes from voltammetric calibrating curves, it is expected that the mass transport characteristics in sample solutions and in calibrating standards are identical. Standard addition methods are used in analytical practice when making calibrating standard with transport properties matching that of the samples would be difficult. Voltammetric measurements can also be carried out in soil—in sediment—or in gel samples. The mass transport conditions in these media, however, can considerably differ from those existing in aqueous solutions. The application of standard addition technique, however, is not an option there. In this work, a glassy carbon electrode was applied with a built-in diffusion layer on its measuring surface and chronoamperometric measurements were carried out. The current–time transients taken in aqueous solution and in tortuous, diffusion-hindered media were compared. Ascorbic acid and iodine as analytes as well as silica sand sediments and green pepper pulps as tortuous matrices were used. It was proved that if the modified electrode is used for analysis, then short time chronoamperometric transients taken in tortuous media can be evaluated by calibration data taken in aqueous standard solutions. 相似文献
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XRF方法在铜镍尾矿分析中的应用 总被引:1,自引:1,他引:0
介绍了XRF方法在铜镍尾矿分析中的基本原理,讨论了湿度、压样力度、基体效应对测量结果的影响,建立了基体效应校正模型。对某矿区的铜镍尾矿样品进行了分析。结果表明,该法精密度好,测定Cu的相对标准偏差为1.215%,N i为1.768%,可实现铜镍尾矿中Cu、N i元素含量的准确、无损、快速分析。 相似文献
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Energetics of bond dissociation, especially the R-H bond heterolysis free energy (pK(a)), has played a central role in promoting chemistry to become a rational science. Despite the oceans of acidity studies in the literature, the current knowledge is limited to that in the classical molecular solvents and is unable to be extended to anticipate the acidity changes in ionic media. As the latter is now very popular for replacing volatile organic solvents, it becomes highly desirable to know how the driving force of bond cleavage is varied as the medium composition is switched from neutral molecules to the charged ions. Here we describe a general approach to measure absolute pK(a)'s in pure ionic liquid (IL). The standard conditions warranting accurate measurement were outlined. The pK(a)'s of the selected 18 C-H type indicator acids in four ILs were determined and a convenient indicator platform was constructed for easy expansion of acidity scales. These absolute pK(a)'s make possible, for the first time, direct comparisons of bond energies in IL with those in molecular solvent and in the gas phase and should be able to serve as the standard parameters for calibrating computational methods suitable for the studies in ionic media. The effect of cation and anion in IL in relation to structure was analyzed. 相似文献